Many communications standards require accurate regulation of transmitted power. This regulation depends in some cases not only upon the total radio link power, but also on data rates and signal formats. As an example, the CDMA 2000 standard has defined requirements for accurate transmit power control such as open loop and closed loop power control in the reverse link. These requirements also define relative code channel power requirements for each of the multiple code channels (for example pilot, FCH (Fundamental Channel), SCH (Supplemental Channel), DCCH (Dedicated Control Channel)) according to their data rates and signal formats. A detailed breakdown of the actual requirements for CDMA 2000 can be found in section 2.1.2 of IS-2000 hereby incorporated by reference in its entirety.
However, these kinds of requirements are not unique to IS-2000. Many other communication standards also have similar requirements for relative code channel powers. A few examples of other standards which include such requirements are 3GPP UMTS, 3GPP2 1xEVDO.
Conventional arrangements for implementing power control in such multiple code channel systems feature a controller which, in the digital domain, determines a gain for each of the channels which is to be active at a given time, subject to the relative code channel power requirement. These gains are then used to control digital gain elements. The outputs of the digital gain elements are combined, and normalized such that the sum of the channels has a more or less constant overall power. The output of the normalizer is then subject to further digital and RF processing before transmission. If the values of the individual digital gains provide a normalized total combined power, the digital portion of the transmitter does not need to include the normalizer.